A dangerous drug-resistant bacterium has been spreading among patients in Southern California, according to a study by Los Angeles County public health officials.

Study author Dawn Terashita, an epidemiologist with the Los Angeles County Department of Public Health, discovered 356 cases of the super bug, known as carbapenem-resistant Klebsiella pneumonia (CRKP), at health facilities in Los Angeles County.

Most of the victims were elderly patients at nursing facilities and long-term care facilities.

"The scary part about these cases are it's a bacteria that is pretty common but develops resistance to most of the antibiotics we have," explained Dr. Andrew Fishman of Good Samaritan Hospital.

"These are usually in patients who had previously been in a nursing home or other hospitals or have seen a course of antibiotics or several courses of antibiotics and as a result the bacteria becomes resistant to most of the antibiotics we use," he added.

CRKP is generally spread through person-to-person contact. Those who catch the bug often tend to display pneumonia-like symptoms. For those who are already in poor health, CRKP can be deadly.

"This is scary stuff. It cannot be treated with any antibiotic that we know of," he said. "We're at the point with some of this (resistant bacteria) that we're just mixing a bunch of crap together, throwing it at the patient and crossing our fingers."

Health officials say that for the time being the bug seems to be mostly limited to Southern California.